Cyanine dyes and a process for preparing them



Patented Apr. 11, 1939 GYANINE ,DYES- AND A PROCESS FOR PREPARING THEM John David Kendall, Ilford, England, assignor to Ilford Limited, Ilford, England, a British com- No Drawing. Application December 21, 1934, Serial No. 758,647. In Great Britain December 11 Claims.

This invention consists in improvements in or relating to the production of compounds containing an ethylenic linkage, or a methine or a polymethine chain, and more particularly to compounds containing two polyvalent elements or groups of elements joined together by such a linkage or chain.

The methine chain consists of the group in which X represents hydrogen or any other monovalent non-metallic element or grouping. The polymethine chain contains a number of methine groups, an example being (where R1, R2 and R3 may be hydrogen, alkyl, aryl or aralkyl groupings, or R1 and R2 may be part of an arylene residue as in indene) with a quaternary salt of a heterocyclic nitrogen compound containing a thio ether or seleno ether grouping including aryl or alphyl or aralphyl thioethers and selenoethers. The quarternary salt of the thio or seleno ether may be derived from an alkyl thione or selenone by reacting with an alkyl salt, as is shown by the following general formula in which X represents the remainder of a heterocyclic radical, R is an alkyl radical and Y is an acid radical:

in ea h case the quarternary salt of the thio or selen ether may be formed either before or simult eously with the reaction with the cyclo- 55 penta iene compound.

Examples of compounds containing the grouping are plain and substituted cyclopentadienes and indenes.

Examples of compounds containing reactive thioether, thione or like groupings which can be condensed with the bodies of the type described are those having a reactive alkyl, aryl or aralkyl mercapto group in the 1x01 7 position such as quaternary salts of the following ,compounds which may be substituted or unsubstituted: alkyl quinoline-Z-thiones, alkyl mercaptothiazoles, alkyl mercapto oxazoles, alkyl mercapto pyridines alkyl mercapto diazoles, alkyl mercapto quinazolines, alkyl mercapto pyrimidines, alkyl mercapto phthalazines and alkyl mercapto indolenines (e. g. a 2-methylmercapto-3:3-di methylindolenine) These two types of compounds interact (in the manner shown inthe following general equation) to form a new type of carbocyanine compound (of the general formula given in the following equation) in which the polymethine chain of the normal carbocyanine compound is replaced by Several specific examples are given below in order to illustrate the process according to the invention.

CYCLOPENTADIENE CONDENSATION EXAMPLE I 2,2 dimethyl 7, 7-di-methenyZ-thiocarbocyam'ne bromide having the structural formula 5 gm. of methylmercapto benzthiazole and 5.2 gm. of methyl-p-toluene sulphonate were heated together for 4 hours at l30-140 C. 6 cc. of cyclopentadiene and 20 cc. of pyridine were then added and the mixture was refluxed for hour. It was then poured into an aqueous solution of potassium bromide and allowed to stand when a precipitate was formed. This was filtered off and recrystallised from hot spirit to give yellow crystals melting at 252 C., with decomposition.

This dye so produced is a sensitiser for silver chloride emulsions and sensitises over a band from x 4600-5700 A. with a maximum at x 4950 A.

EXAMPLE II 2,2'-dz'ethyl-7 ,7 -di-methenyl-thiocarbocyaninebromide This compound was prepared in a manner similar to that described in Example I but using ethyl-p-toluene sulphonate. The product was a dye in the form of yellow crystals, melting at 265 C. with decomposition. This dye is a sensi tiser for silver chloride emulsion sensitising over a band from A 4600 to 6100 A, with a maximum at A 4950 A.

The corresponding iodide 2,2'-diethyl-7,7'- ethylene-thiocarbooyanine-iodide was obtained, in a similar manner with the substitution of potassium iodide solution for the potassium bromide solution as yellow crystals melting at 265 C.

This dye is a sensitiser for silver chloride and iodobromide emulsions and sensitises over a band from 7\ 4400-5300 A, with a maximum at about i 5000 A.

EXAMPLE III 1,1 dimethyl 9,9-di-methenyZ-2,2-carbocyanine bromide, having the structural formula OH; Br CH3 2.5 gm. of 1-methyl-quinoline-2-thione and 2.7 gm. of ethyl p-toluene sulphonate were heated together for four hours at ISO-140 C. 5 cc. of cyclopentadiene and 20 cc. of pyridine were then added and the mixture refluxed for one hour. The mixture was then poured into an aqueous solution of potassium bromide when a solid separated out which was filtered off and recrystallised from methyl alcohol to give red brown crystals melting at 268 C.

This dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about A 6200 A. with a maximum at about A 5700 A.

EXAMPLE IV 1 ,1 -diethyZ-9',9' -di-methenyZ-2 ,2 -carbocyanine bromide This compound was obtained, as green crystals melting at 268 C., from l-ethyl quinoline-2- thione by a method similar to that described in Example III.

This dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to A 6200 A. with a maximum at x 5300 A.

EXAMPLE V 2,2 dimethyl 4,5,4',5'-tetm0a:y-dimethenyl- 7,7 di methanol thio-carbocyanine-p-toluene sulphonate was obtained by a method similar to that of Example III from 1-methylmercapto-4,5- dioxymethylene benzthiazole, methyl-p-toluene sulphonate, and cyclopentadiene, as red needles with a blue reflex, melting at 308 C.

The dye is a sensitiser for silver chloride and iodobromide emulsions sensitising over a band from about 4400-5700 A. with a maximum at about i 5200 A.

EXAMPLE VI 2,2 diethyl 4,5,4,5 tetraomy-dimethylene- 7 ,7'-di-methenyl thz'ocarbocyanine-p-toluene sulphonate was prepared by a method similar to that of Example III, using ethyl-p-toluene sulphonate, as brown yellow crystals melting at 295 C.

The dye is a sensitiser for silver chloride and iodobromide emulsions sensitising over a band from about A 4400 to 5700 A. with a maximum at about A 5200 A.

EXAMPLE VII 2,2 dimethyl 4,5,4,5'-tetramethoxy-7,7'-dimethenyZ-thiocarbocyanine-p-toluene sulphonate was obtained by a method similar to that of EX- ample III, from 1-methyl-mercapto4,5-dimethoxy benzthiazole methyl-p-toluene sulphonate and cyclo pentadiene, as orange yellow crystals melting at 296 C.

The dye is a sensitiser for silver chloride and iodobromide emulsions sensitising over a band from about i 4000 m x 5900 A. with an indeterminate maximum at about A 4800 A.

EXAMPLE VIII 2,2-- diethyl 4,5,4',5 tetrametlwmy 7,7'-dz'- methenyl-thiocarbocyanine-p-toluene sulphonate was obtained by a method similar to that of EX- ample III, from 1-methylmercapto-4,5-dimethoXy-benzthiazole-ethyl-p-toluene sulphonate and cyclopentadiene, as orange red crystals melting at 280 C.

The dye is a sensitiser for silver chloride and iodobromide emulsions and sensitises over a band from about I 4400 to 5700 A. with an indeterminate maximum at about A 5100-5200 A.

EXAMPLE IX A thiocarbocyanine from di-methylmercapto thio 5,5 diazole and cyclo pentadiene, having the structural formula 2.0 gm. of di-methylmercapto thio-aa-dlazole which has the structural formula:

and 5.6 gm. of methyl-p-toluene sulphonate were heated together for four hours-at -1-40 C. 8 cc. of cyclopentadiene and 20 cc. of pyridine were then added and the mixture refluxed for 1 hour after which it was poured into an aqueous solutionof potassium iodide. On standing dark green crystals separated out and were filtered off, washed and this precipitate was boiled with cc. of spirit and filtered hot and the filtrate allowed to cool when yellow crystals melting at 224 C. were deposited.

The dye is a sensitiser for silver chloride emulsion and sensitises over a band from about 4200-5000 A. with a maximum at about i 4750 A.

EXAMPLE X A thiocarbocyanine iodide dyestuii was obtained by a method similar to that of Example IX from dimethylmercapto thio 5,5 diazole, ethyl p-toluene' sulphonate and cyclo pentadiene, as small yellow needles melting at 202 C.

The dye is a. sensitiser for silver chloride and iodo bromide emulsions sensitising over a band from about 4200-5100 A. with a maximum at about X 4800 A.

EXAMPLE XI 2,2'-dimethyl-3,-4,3,4'-dibe'nz-Z,7 di methylthio-carbocyanine-p-to=luene sulphonate, was obtained by a method similar to that of Example IX, from 2-methylmercapto 8 naphthathiazolemethyl-p-toluene sulphonate, and cyclo pentadiene, as orange red needles melting at 226 C. The dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about A 5700 A. with a maximum at about x 5300 5.

EXAMPLE XII 2,2'-dim:ethyl 7,7'- dimethenyl owacarbocyanine bromide was prepared by a method similar to that of Example IX from l-methylmercapto benzoxazole, methyl-p-toluene sulphonate and cyclo pentadiene as yellow crystals melting at 240 C.

INDENE CONDENSATIONS-CONDENSATION WITH THIONES EXAMPLE XIII 1,1 -dimethyl 9,9-phenylene 2,2-ca,rbocyaninep-toluene sulphonate-5 gm. of indene 8 gm. of methyl-quinoline-Z-thione and 9 gm. ofethylp-toluene sulphonate were heated together at 130-140" C. for four hours. 15 cc. of pyridine were then added and the mixture refluxed for a quarter of an hour when the mixture became solid. The flask was washed out with some spirit and the crystals filtered ofi and washed with water and ether and recrystallised from methyl alcohol to give green needles, melting at 273 C.

The dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about 7000 A. with amaximum at about 6600 A. and

' a minimum at about A 5400 A.

EXAMPLE? XIV 1,1"- methyl-9,9"- o -phenyZene-LW- carbocyanine bromide CONDENSATIONS WITH METHYLMERCAP- TO COMPOUNDS EXAMPLE XV 2,2'-dimethyZ-7,7'-o-phenyle1te thiocdrbocyanine iodide 2.5 gm. of indene, 8 gm. of l-methylmercaptobenzthiazole and 8.5 gm. of methyl-p-toluene sulphonate were heated together at 130-140 C. for 4 hours. the mixture refluxed for 1 hour after which it was poured into an aqueous solution of potassium bromide. The solid which separated out was filtered off, washed with water, hot benzene and ether, and recrystallised from methyl alcohol, to give red needles melting at 245 C. with decomposition. The dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about i 5900 A. with a maximum at about 5700 A.

EXAMPLE XVI 2,2 -diethyl-7,7-a-phenylene thio carbo'cyamne-p-toluene sulphonate was obtained by a method similar to that of Example XV using water in, place of the potassium bromide solution, as scarlet needles. By pouring the reaction mixture into potassium iodide solution as before the corresponding iodide was obtained as red needles melting at 226-8" C.

Both these dyes are sensitisers for silver iodo- Z bromide emulsions and extend the sensitivity to about i 0000 A.v with a maximum at about A 5600 A.

EXAMPLE XVII 2,4,6,2',436'-he;camethyl-7,7'-o-phenylene 0a:- acarbocya'rvine-iodide was prepared by a method similar to that of Example XV, from indene, lmethylmercapto 4.5-dimethyl-benzoxazole and methyl-p-toluene sulphonate, as yellow brown powder melting at over 300 C.

EXAMPLE XVIII Dimet'hyl -o-phenyle'ne-phthalazooarbocyanine iodide having the structural formula This salt was prepared by a method similar to that of Example XV from methyl mercaptophthalazine, indene, and methyl-p-toluene sulphonate to give a purple dyestuff. The dye is a desensitiser for silver iodobromide emulsions.

20 cc. of pyridine were added and i ll EXAMPLE XIX A number of compounds were-prepared from methyl-mercapto bodies and indene by the following general method:

The methyl mercapto body together with the alkyl-p-toluene sulphonate were heated for about four hours at 130-140 C. The indene was then added together with some pyridine and the mixture refluxed for half to one hour after which it was poured into water if the p-toluene sulphonate of the dye was required or into a solution of the appropriate alkali salt, such as potassium iodide, if a different dye salt was required. The precipitate was filtered off, washed and recrystallised from a suitable solvent usually spirit or methyl alcohol.

Examples of compounds prepared by this method are as follows:

2,2-dimethyZ-7,7'-ophenylene oxacarbocyanine-iodide was prepared from indene, l-methylmercapto-benzoxazole, and methyl-p-toluene sulphonate to yield green crystals with a blue reflux, melting at 270 C. The dye is a sensitiser for silver chloride emulsions and sensitises over a band from about A 4200-5060 A., with a maximum at A 4860 A.

2,2 dimethyl-4,5,4,5'-tetraoa:y dimethylene- 7,7 -o-phenylene-thiocarbocyanine-p-toluene sulphonate was prepared from l-methylmercapto- 4,5-dioxymethylene benzthiazole, indene, and methyl-p-toluene sulphonate, as pale pink needles melting at 244 C.

The dye is a sensitiser for silver chloride and iodobromide emulsions and extends the sensitivity to about A 6000 A. with a maximum at about A 5700 A;

2,2 -diethyl-4,5,4 ',5 -tetra:cydimethyZene-7 ,7 o-phenylene-thio-carbocyaninep toluene sulphonate was prepared from l-methylmercapto- 4,5-dioxymethylene benzthiazole, indene and ethyl-p-toluene sulphonate, as green needles melting at 295 C. The dye is a sensitiser for silver chloride and iodobromide emulsions and extends the sensitivity to A 6200 A. with a maximum at A 5800 A.

2,2-dimethyZ-4,5,4',5'-tetra memory-7,7 0- phenyZene-thiocarbocyanine bromide was prepared from 1 methyl-mercapto-4,5-dlmethoxy benzthiazole, indene, and methyl-p-toluene sulphonate, as golden crystals melting at 260 C. The dye is a sensitiser for silver chloride and iodobromide emulsions and extends the sensitivity to about A 6100 A. with a maximum at about A 5600 A.

2,2-diethyl-4,5,4,5tetramethoxy-7,7-o-phenylene-thio-carbocyanine bromide was prepared from 1-methylmercapto-4,5-dimethoxy benzthiazole, indene, and ethyl-p-toluene sulphonate, as red needles melting at 258 C. The dye is a sensitiser for silver chloride and iodobromide emulsions and extends the sensitivity to about A 6300 A. with a maximum at about A 5600 A. The bromide salt of a dyestufi was obtained from dimethyl-mercapto-thio-fl,fi'-diazole, indene and methyl-p-toluene sulphonate, as red brown needles melting at 218. The dye is a sensitiser for silver iodo bromide emulsions and extends the sensitivity to about A 5700 A. with a maximum at about A 5400 A.

The bromide salt of a dyestuff was obtained from dimethyl-mercapto-thio-13,B'diazole, in dene, and ethylp-toluene sulphonate, as blue needles melting at 202 C. The dyestuff is a structural formula This salt was obtained from 4-methyl-mercapt0- quinazoline, indene, and methyl-p-toluene sulphonate as green crystals melting at 298 C.

1,1 -diethyl-9,9' -o-phertylene- 4,4 -quinazocarbocyanine iodide was prepared from 4-methylmercapto-quinazoline, indene, and ethyl-p-toluene sulphonate as green needles melting at 222 C.

2,2 dimethyl 3,4,3,4- dibenz-7,7-o-phenylene-thio-carbocyanine bromide was prepared from 2 -methylmercapto-fi-naphtha thiazole, methyl-p-toluene sulphonate and indene, as chocolate coloured needles with a gold reflux melting at 208 C.

The dy is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about A 6300 A. with a maximum at A 5800 A.

3,3-dimethyl-2,2-di-methyZmercapto-o-pheviylene-4,4'--pyrimido-carbocyanine-p-toluene sulphonates having the structural formula This salt was prepared from 2,4-di-methylmercapto-pyrimidine, indene and methyl-p-toluene sulphonate, as green rods melting at 306 C.

The dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about A 6700 A. Witha maximum at about A 6100 A.

3,3- diethyl-2,2'-di-methylmercapto-o-phenylene-4,4-pyrimido-carbocyanine bromide was prepared from 2,4-dimethylmercapto-pyrimidine, ethyl-p-toluene sulphonate, and indene, as green needles melting at 270 C.

The dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about A 6600 A. with a maximum at about A 5800 A.

1,1 -dimethyl-7,7'-o-phenylene -2,2- pyridocarbocyanine iodide was prepared from 2-methyl mercaptopyridine, 3-methyl p toluene-sulphonate, and indene, as green prismatic needles melting at 268 C.

The dye is a sensitiser for silver chloride and iodobromide emulsions and sensitisers over a band from. about 4700 to 6400 A. with a maximum at about 5500 A.

3,3 -dimethyZ-2,2',6,6- tetmmethylmercapto-ophenylene 4,4 pyrimido carbocyam'ne bromide having the structural formula This salt was prepared from 2,4,6-trimethyl mercapto pyrimidine, indene, and methyl-p -toluene sulphonate, as a dark reddish green dyestuff.

The dye is a sensitiser for silver iodobromide emulsions and extends the sensitivity to about 6800 A. with a maximum at about 6000 A.

I claim:

1. A 2,2-dialkyl-7,7'-dimethenyl-thiocarbocyanine salt.

2. A 2,2'-dialkyl-7,'7phenylene thiocarbocyanine salt.

3. A 1,1'-dialphyl-9,9'- ethylene 2,2- carbocyanine salt.

4. The process for the production of a new class of organic compounds comprising condensing in solution and in the presence of an acid binding agent, a compound selected from the group consisting of indene and cyclo-pentadiene with an alkyl quaternary salt of a heterocyclic nitrogen compound of the type used in the production of cyanine dyes, having a thioether group substituted in a position selected from the class consisting of alpha and gamma positions to the nitrogen atom.

5. The process of claim 4 wherein the alkyl quaternary salt of the heterocyclic nitrogen compound is formed in situ by reacting an alkyl salt with a compound selected from the group consisting of N-alkyl thione and alkyl mercapto bases of the corresponding heterocyclic nitrogen compound.

6. The process of claim 4 wherein the alkyl quaternary salt of the heterocyclic nitrogen compound is preformed by reacting an alkyl salt with a compound selected from the group consisting of N-alkyl thione and alkyl mercapto bases of the corresponding heterocyclic nitrogen compound.

'7. A process for the production of a new class of organic compounds by condensing a compound selected from the group consisting of indene and cyclopentadiene with an alkyl quaternary salt of a heterocyclic nitrogen compound of the type used in the production of cyanine dyes having a thioether group substituted in a position selected from the class consisting of a and 7 positions to the nitrogen atom wherein said salt is prepared by fusing a compound selected from the group consisting of N -alkyl thiones and alkyl mercapto bases of the corresponding nitrogen compound with an alkyl salt in the presence of the compound selected from the class consisting of indene and cyclopentadiene, adding an acid binding solvent and heating to complete the condensation reaction.

8. The process of claim 4 wherein the alkyl quaternary salts of the heterocyclic nitrogen compounds containing thioether groupings are derived by reacting the corresponding heterocyclic nitrogen base containing a thione grouping with an alkyl salt.

9. The process of claim 4 wherein a compound selected from the group consisting of indene and cyclopentadiene is reacted with an alkyl quaternary salt of 1-methylmercapto-benzthiazole.

10. The process of claim 4 wherein a compound selected from the group consisting of indene and cyclopentadiene is reacted simultaneously with l-ethyl-quinoline-Z-thione and an alkyl salt.

11. A dye having the following general formula:

JOHN DAVID KENDALL.

Certificate of Correction Patent No. 2,153,927. April 11, 1939.

JOHN DAVID KENDALL- It is hereby certified that errors appear in the printed specification of the above numbered patent requiring correction as follows: Page 1, first column, line 38, for quarternary read quaternary; page 2, second column, line 15, Example V, for dimethenyl read dimethylene; page 3, first column, line 38, Example XI, for "4-dibenz-7,7-dimethyl-" read 4-dibenz-7,7'-dt-methenyl-; page 5, second column, line 33, in the formula for GR =CR read (113 0132; and that the said Letters Patent should be read With these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 1st day of August, A. D. 1939.

[SEAL] HENRY VAN ARSDALE,

Acting Commissioner of Patents. 

